Morbidity from abdominal radiotherapy in the First United Kingdom Children's Cancer Study Group Wilms' Tumour Study. United Kingdom Children's Cancer Study Group.

Between 1980 and 1986, 384 children were entered into the UKCCSG First Wilms' Tumour Study (UKW1). For 171 patients receiving abdominal radiotherapy (RT) the early and late toxicity has been analysed. Major early toxicity was significantly more likely with whole abdominal (48%) compared with flank (21%) RT (P = 0.007). An increased risk of major early toxicity, which did not reach statistical significance, was seen with right (20.5%) compared with left (7%) flank RT (P = 0.063) and in those treated with a RT dose of > 20 Gy compared with a dose of < or = 20 Gy (P = 0.103). There were 138 evaluable survivors, with a median follow-up of 127 months. Of these, 33 (23.9%) were reported to have late effects, including 27 musculoskeletal (19.6%), four gastrointestinal (2.9%), and three (of 68 girls) ovarian failure (4.4%). There was no apparent effect of age at diagnosis, RT dose or field size on the risk of developing late effects. The continued surveillance of the long term survivors of Wilms' tumour for the late effects of treatment will be important.